Here are the minimum system requirements. Looks like to me you meet the minimum requirements. You can run the game, I would recommend turning down all the eye candy and such for smoother gameplay.

• 3D Hardware Accelerator Card required - 100% DirectX® 9.0b compatible 64MB Hardware T&L - capable video card and latest drivers
• Pentium® III 500MHz or Athlon® 500MHz processor or higher for systems with Windows® 98/ME
• Pentium® III 500MHz or Athlon® 500MHz processor or higher for systems with Windows® 2000/XP
• Original version of Microsoft® Windows® 98/ME/2000/XP
• 64MB of RAM (256MB recommanded)
• 575MB of uncompressed free hard disk space
• 100% DirectX® 9.0b compatible 16-bit sound card and latest drivers
• 100% Windows® 98/ME/2000/XP compatible mouse, keyboard and latest drivers
• DirectX® 9.0b

What I would do in your case, download the demo and give it a shot. If you like it and it runs smoothly purchase the full retail version

Direct link to the demo

Also what OS do you run? You can get more performance by killing a lot of background processes. I can help you with this, if you are seriously interested.